Electrodeposition of thermally stable alloys

ABSTRACT

A method includes immersing a wafer in an electrolyte including a plurality of compounds having elements of a thermally stable soft magnetic material. The method also includes applying a combined stepped and pulsed current to the wafer when the wafer is immersed in an electrolyte. The wafer is removed from the electrolyte when a layer of the thermally stable soft magnetic material is formed on the wafer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.16/411,629, filed on May 14, 2019, now U.S. Pat. No. 11,152,020, whichclaims priority to U.S. provisional application number 62/671,125, filedon May 14, 2018, the contents of which are hereby incorporated byreference in their entireties.

SUMMARY

Various embodiments of the disclosure generally relate to formingthermally stable elements (e.g., thermally stable reader shields inrecording heads or read heads). In different embodiments,electrodeposition or electroplating may be used to form the thermallystable elements with the high damping materials.

In one embodiment, a method is provided. The method includes immersing awafer in an electrolyte including a plurality of compounds havingelements of a thermally stable soft magnetic material. The method alsoincludes applying a combined stepped and pulsed current to the waferwhen the wafer is immersed in the electrolyte. The wafer is removed fromthe electrolyte when a layer of the thermally stable soft magneticmaterial is formed on the wafer.

In another embodiment, an electrolyte is provided. The electrolyteincludes H₃BO₃ having a concentration in a range of between about 0.15to about 0.6 moles/liter, Ni²⁺ having a concentration in a range ofbetween about 0.36 to about 0.78 moles/liter, and Fe²⁺ having aconcentration in a range of between about 5 to about 20 millimolar. Theelectrolyte further includes a 4 d or 5 d transition element having aconcentration in a range of between about 0.1 to about 0.2 millimolar.

In yet another embodiment, a recording head is provided. The recordinghead includes at least one of a read head or a write head. The recordinghead also includes at least one thermally stable feature formed of amaterial having grains that include at least one element and a dopant.Each of the grains of the material has a size between about 6 nanometersand about 12 nanometers.

Other features and benefits that characterize embodiments of thedisclosure will be apparent upon reading the following detaileddescription and review of the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of a data storage device in whichembodiments of the present application can be used.

FIG. 2 is a schematic diagram of a cross-section of one embodiment of arecording head that reads from and writes to a storage medium.

FIG. 3 is a bearing surface view of a magnetic reproducing device havinga read sensor.

FIGS. 4A, 4B and 4C are simplified diagrams that illustrate a comparisonbetween a structure of a soft magnetic material formed by a currentelectrodeposition technique and structures of soft magnetic materialsformed in accordance with embodiments of the disclosure.

FIG. 5 is a diagrammatic illustration of an electroplating system inaccordance with one embodiment.

FIGS. 6A, 6B and 6C show magnetic hysteresis loops obtained forNi_(78.5)Fe_(21.5).

FIGS. 7A, 7B and 7C show magnetic hysteresis loops obtained for NiFeX.

FIG. 8A is an image of a Ni_(78.5)Fe_(21.5) layer generated fromtransmission electron microscopy (TEM).

FIG. 8B is an image of a Ni_(78.5)Fe_(21.5) layer generated from amagnetic force microscope (MFM).

FIG. 8C shows a magnetic hysteresis loop obtained forNi_(78.5)Fe_(21.5).

FIG. 9A is an image of a NiFeX₁ layer generated from TEM.

FIG. 9B is an image of a NiFeX₁ layer generated from a MFM.

FIG. 9C shows a magnetic hysteresis loop obtained for NiFeX₁.

FIG. 10A is an image of a NiFeX₂ layer generated from TEM.

FIG. 10B is an image of a NiFeX₂ layer generated from a MFM.

FIG. 10C shows a magnetic hysteresis loop obtained for NiFeX₂.

FIG. 11 is a graph that shows a presence of a composition gradient in apatterned wafer.

FIG. 12 is an image of a NiFeX layer formed using galvanostatic platingand subjected to high temperature annealing.

FIG. 13A is an image of a NiFeX layer formed using stepped currentplating and subjected to high temperature annealing.

FIG. 13B is an example of a stepped current waveform that may beutilized to form the NiFeX layer shown in FIG. 13A.

FIG. 14A shows a Magneto optical Kerr domain image of anNi_(78.5)Fe_(21.5) layer after carrying out an annealing operation onthe Ni_(78.5)Fe_(21.5) layer.

FIG. 14B shows atomic force microscope (AFM) and MFM images of a portionof the Ni_(78.5)Fe_(21.5) layer shown in FIG. 14A.

FIG. 15A shows a Magneto Optical Kerr domain image of a NiFeX₂ layerafter carrying out an annealing operation on the NiFeX₂ layer.

FIG. 15B shows AFM and MFM images of a portion of the NiFeX₂ layer shownin FIG. 15A.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the disclosure generally relate to forming thermallystable elements (e.g., thermally stable reader shields in recordingheads or read heads). The formation of the thermally stable readshields, for example, enables annealing operations on the read heads tobe carried out at high temperatures (e.g., temperatures greater than orequal to 350 degrees Celsius (° C.)), which leads to improvedperformance of the read heads. In different embodiments,electrodeposition or electroplating may be used to form the elements.However, prior to providing additional details regarding the differentembodiments, a description of an illustrative operating environment isprovided below.

FIG. 1 shows an illustrative operating environment in which certainspecific embodiments disclosed herein may be incorporated. The operatingenvironment shown in FIG. 1 is for illustration purposes only.Embodiments of the present disclosure are not limited to any particularoperating environment such as the operating environment shown in FIG. 1. Embodiments of the present disclosure are illustratively practicedwithin any number of different types of operating environments.

It should be noted that the same reference numerals are used indifferent figures for same or similar elements. It should be understoodthat the terminology used herein is for the purpose of describingembodiments, and the terminology is not intended to be limiting. Unlessindicated otherwise, ordinal numbers (e.g., first, second, third, etc.)are used to distinguish or identify different elements or steps in agroup of elements or steps, and do not supply a serial or numericallimitation on the elements or steps of the embodiments thereof. Forexample, “first,” “second,” and “third” elements or steps need notnecessarily appear in that order, and the embodiments thereof need notnecessarily be limited to three elements or steps. It should also beunderstood that, unless indicated otherwise, any labels such as “left,”“right,” “front,” “back,” “top,” “bottom,” “forward,” “reverse,”“clockwise,” “counter clockwise,” “up,” “down,” or other similar termssuch as “upper,” “lower,” “aft,” “fore,” “vertical,” “horizontal,”“proximal,” “distal,” “intermediate” and the like are used forconvenience and are not intended to imply, for example, any particularfixed location, orientation, or direction. Instead, such labels are usedto reflect, for example, relative location, orientation, or directions.It should also be understood that the singular forms of “a,” “an,” and“the” include plural references unless the context clearly dictatesotherwise.

FIG. 1 is a schematic illustration of a data storage device 100including a data storage medium and a head for reading data from and/orwriting data to the data storage medium. In data storage device 100,head 102 is positioned above storage medium 104 to read data from and/orwrite data to the data storage medium 104. In the embodiment shown, thedata storage medium 104 is a rotatable disc or other storage medium thatincludes a storage layer (e.g., a magnetic storage layer) or layers. Forread and write operations, a spindle motor 106 (illustratedschematically) rotates the medium 104 as illustrated by arrow 107 and anactuator mechanism 110 positions the head 102 relative to data tracks114 on the rotating medium 104 between an inner diameter 108 and anouter diameter 109. Both the spindle motor 106 and actuator mechanism110 are connected to and operated through drive circuitry 112(schematically shown). The head 102 is coupled to the actuator mechanism110 through a suspension assembly which includes a load beam 120connected to an actuator arm 122 of the mechanism 110 for examplethrough a swage connection. Although FIG. 1 illustrates a single loadbeam coupled to the actuator mechanism 110, additional load beams 120and heads 102 can be coupled to the actuator mechanism 110 to read datafrom or write data to multiple discs of a disc stack. The actuatormechanism 110 is rotationally coupled to a frame or deck (not shown)through a bearing 124 to rotate about axis 126. Rotation of the actuatormechanism 110 moves the head 102 in a cross track direction asillustrated by arrow 130.

The head 102 includes one or more transducer elements (not shown in FIG.1 ) coupled to head circuitry 132 through flex circuit 134. Detailsregarding elements of a head such as 102 are provided below inconnection with FIG. 2 .

FIG. 2 is a schematic diagram showing a cross-sectional view of portionsof a recording head 200 and a data storage medium 250 taken along aplane substantially normal to a plane of a bearing surface (for example,an air bearing surface (ABS)) 202 of recording head 200. The recordinghead elements shown in FIG. 2 are illustratively included in a recordinghead such as recording head 102 in FIG. 1 . Medium 250 is illustrativelya data storage medium such as medium 104 in FIG. 1 . Those skilled inthe art will recognize that recording heads and recording media commonlyinclude other components. Embodiments of the present disclosure are notlimited to any particular recording heads or media. Embodiments of thepresent disclosure may be practiced in different types of recordingheads and media.

Recording head 200 includes a write pole 205, a magnetization coil 210,a return pole 215, a top shield 218, a read transducer 220, a bottomshield or leading shield 222 and a wafer overcoat 224. Storage medium250 includes a recording layer 255 and an underlayer 260. Storage medium250 rotates in the direction shown by arrow 265. Arrow 265 isillustratively a direction of rotation such as arrow 107 in FIG. 1 .

In an embodiment, electric current is passed through coil 210 togenerate a magnetic field. The magnetic field passes from write pole205, through recording layer 255, into underlayer 260, and across toreturn pole 215. The magnetic field illustratively records amagnetization pattern 270 in recording layer 255. Read transducer 220senses or detects magnetization patterns in recording layer 255, and isused in retrieving information previously recorded to layer 255.

In embodiments of the disclosure, bottom shield or trailing shield 222is formed of a thermally stable material, which allows for the use ofhigh temperatures (>=350° C.) for annealing operations during formationof read transducer 220. Different layers of an embodiment of a readtransducer or read sensor that employs a bottom shield or trailingshield 222 is shown in FIG. 3 and described below.

FIG. 3 is a schematic block diagram illustrating an example read head300 including a magnetoresistive sensor 302. The magnetoresistive sensor302 is positioned between top shield 218 and bottom shield 222. Top andbottom shields 218 and 222 reduce or substantially block extraneousmagnetic fields, such as, for example, those from adjacent bits on datadiscs from impacting the magnetoresistive sensor 302, thus improving theperformance of the magnetoresistive sensor 302. In one implementation,the top and bottom shields 218 and 222 permit magnetic fields from thebit directly under magnetoresistive sensor 302 to affect themagnetoresistive sensor 302, and thus be read.

The magnetoresistive sensor 302 may include a plurality of layersincluding a sensor antiferromagnetic (AFM) layer 304, a sensor stacksynthetic antiferromagnetic (SAF) structure 306, a spacer layer 308, afree layer or sensing layer 310 and a stack cap 312. A SAF shieldingstructure 314 and an AFM layer 315 may optionally be included above thestack cap 312. Dashed lines are used to represent elements of SAFstructure 314 and AFM layer 315 to indicate that these structures areoptional.

In the embodiment shown in FIG. 3 , the sensor SAF structure 306includes a pinned layer 316 a thin separation layer 318, which maycomprise a metal such as ruthenium (Ru) in some embodiments, and areference layer 320. The magnetic moments of each of the pinned layer316 and the reference layer 320 are not allowed to rotate under magneticfields in the range of interest (for example, magnetic fields generatedby the bits of data stored on the data discs). The magnetic moments ofthe reference layer 320 and the pinned layer 316 are generally orientednormal to the plane (e.g., the y direction) of FIG. 3 and anti-parallelto each other.

The magnetic moment of the free layer 310 is free to rotate under theinfluence of an applied magnetic field in a range of interest. The readhead 300 further includes side biasing magnets or side shields 322,which produce a magnetic field that biases the free layer 310 with amagnetic moment parallel to the plane of the figure and generallyoriented horizontally. This bias prevents the magnetic moment of thefree layer 310 from drifting due to, for example, thermal energy, whichmay introduce noise into the data sensed by the read head 300. The biasis sufficiently small, however, that the magnetic moment of the freelayer 310 can change in response to an applied magnetic field, such as amagnetic field of a data bit stored on the data discs. In someembodiments, the side biasing magnets or side shields 332 are formed ofsoft magnetic material (e.g., material that can be easily magnetized anddemagnetized at relatively low magnetic fields). The soft magneticmaterial may be an alloy comprising Ni and Fe. The magnetoresistivesensor 302 is separated and electrically isolated from the side biasingmagnets 322 by an isolation layer 324 including, for example, insulatingmaterials. Isolation layer 324 may also be present in other regions ofhead 300 as shown in FIG. 3 .

In the embodiment shown in FIG. 3 , optional SAF shielding structure 314includes a SAF shield reference layer 326, a thin SAF shield separationlayer 328, which may comprise a metal such as Ru in some embodiments,and a SAF shield pinned layer 330. Because, in some embodiments, sensor300 utilizes soft side shields 322, SAF shield reference layer 326 has arelatively fixed magnetization to assist in stabilizing themagnetizations of side shields 322. Thus, in such embodiments, an AFMlayer 315 pins the magnetization of SAF shield pinned layer 330substantially parallel to the bearing surface, which results in therelatively fixed magnetization of SAF shield reference layer 326 due toantiferromagnetic coupling across SAF shield separation layer 328 andthus in stabilizing the magnetizations of the side shields 322substantially parallel to the bearing surface as well. SAF shieldreference layer 326 and SAF shield pinned layer 330 may be formed of asoft magnetic material (for example, an alloy comprising Ni and Fe). Itshould be noted that, instead of employing SAF shielding structure 314and AFM layer 315, side shields 322 may be stabilized by shapeanisotropy, by employing hard magnetic layers adjacent to the softmagnetic layers within side shield 322, or by any other suitabletechnique.

In some embodiments, sensor 302 may utilize tunnel magnetoresistance(TMR) or giant magnetoresistance (GMR) effects. In embodiments thatutilize TMR effects, spacer layer 308 is a tunneling barrier layer(e.g., a MgO barrier layer) that separates the SAF structure 306 fromthe free layer 310. The tunneling barrier layer 308 is sufficiently thinthat quantum mechanical electron tunneling occurs between a referencelayer 320 in the SAF structure 306 and the free layer 310. The electrontunneling is electron-spin dependent, making the magnetic response ofthe magnetoresistive sensor 302 a function of the relative orientationsand spin polarizations of the SAF structure 306 and the free layer 310.The highest probability of electron tunneling occurs when the magneticmoments of the SAF structure 306 and the free layer 310 are parallel,and the lowest probability of electron tunneling occurs when themagnetic moments of the SAF structure 306 and the free layer 310 areantiparallel. Accordingly, the electrical resistance of themagnetoresistive sensor 302 changes in response to an applied magneticfield. The data bits on the data discs in the disc drive may bemagnetized in a direction normal to the plane of FIG. 3 , either intothe plane of the figure, or out of the plane of the figure. Thus, whenthe magnetoresistive sensor 302 passes over a data bit, the magneticmoment of the free layer 310 is rotated either into the plane of FIG. 3or out of the plane of FIG. 3 , changing the electrical resistance ofthe magnetoresistive sensor 302. The value of the bit being sensed bythe magnetoresistive sensor 302 (for example, either 1 or 0) maytherefore be determined based on the current flowing from a firstelectrode (not shown) to a second electrode (not shown) connected to themagnetoresistive sensor 302.

Formation of read head 300 involves performing one or more annealingoperations on layers of the read head 300. Advanced reader technologymay employ a high reader annealing temperature (e.g., >=350° C.,compared to annealing temperatures of 300° C. or less employed forcurrent readers or baseline readers) to achieve a good TMR ratio (e.g.,about 15% TMR gain), to realize high density and low noise readerperformance. A reader bottom shield such as 222 with good thermalstability in grain structure, magnetics and domain behavior helpsimprove reader performance. Some current readers employ electrodepositedNi_(78.5)Fe_(21.5) as a bottom shield 222 material, which may notsustain annealing temperatures >300° C. For example, annealingtemperatures >300° C. applied to readers having the currently-employedbottom shield material may result in the bottom shield 222 losinganisotropy and having a poor post-annealing domain structure. Further, agrain size increase from about 20 nanometers (nm) before annealing toabout 350 nm after annealing may take place. Such post annealing changesmay cause a relatively large increase in reader noise.

Embodiments of the disclosure provide a thermally stable soft magneticmaterial that is capable of withstanding annealing temperatures >350°C., and may therefore be utilized as a shield material (e.g., as amaterial that forms bottom shield 222) for advanced reader applications,for perpendicular magnetic recording (PMR) heads, heat assisted magneticrecording (HAMR) heads, etc. Embodiments of the disclosure may also beutilized to provide thermally stable soft magnetic or nonmagneticmaterials for micro-electro-mechanical systems (MEMS), micro-actuators,magnetoresistive random access memory (MRAM) and inductor applications.

FIGS. 4A, 4B and 4C are simplified diagrams that illustrate a comparisonbetween a structure of a soft magnetic material 400 formed by a currentelectrodeposition technique and structures of soft magnetic materials410 and 420 formed in accordance with embodiments of the disclosure,which are described in detail further below. In FIG. 4A, the softmagnetic material 400 includes soft magnetic alloy (e.g., NiFe) grains402 and an additive or dopant 404 that reacts with, or resides at,boundaries of grains 402. In contrast, in embodiments of the disclosureshown in FIGS. 4B and 4C, soft magnetic materials 410 and 420 includesolute atoms (e.g., dopant atoms) 414 and 424, respectively, thatdistort lattices to deflect or trap vacancies in the lattices within agrain, and thereby do not reside at grain boundaries. As can be seen inFIGS. 4B and 4C, there may be a substantial size mismatch between thesolute atom 414, 424 and a Ni/Fe atom 412, 422. In the structure 410 ofFIG. 4B, solute atom 414 is substantially smaller than the Ni/Fe atom412. In the structure of FIG. 4C, the solute atom 424 is substantiallylarger than the Ni/Fe atom 422. The high atomic size mismatch (between412 and 414 in FIG. 4B, and between 422 and 424 in FIG. 4C) isbeneficial for melting points. An electrodeposition method for forming,for example, an X doped NiFe film (where X may be Re or another 4d/5dhexagonal close-packed (hcp)/face centered cubic (fcc) transition metalsuch as Os, Ir, Pt, Rh, Pd, Ag, etc.) having a structure of the typeshown in FIG. 4B or FIG. 4C in accordance with one embodiment isdescribed below in connection FIG. 5 . Doping concentrations and otherdetails are provided further below in the description of FIG. 5 .

FIG. 5 is a diagrammatic illustration of anelectrodeposition/electroplating system 500 in accordance with oneembodiment. Electroplating system 500 includes control circuitry 502 anda plating tank 504. Plating tank 504 includes a container 506, an anode508, a cathode 510, a paddle assembly 512, a solution or electrolyte514, cathodic thief elements 516 and a magnet 518.

Container 506 may be made of any suitable material, which may not beelectrically conductive (e.g., glass or plastic). Anode 508 ispositioned within the container 506 and may be located relatively closeto a bottom of the container 506 as shown in FIG. 5 . Anode 508 may beformed of a wire mesh or a combination of a plate and a wire mesh. Theplate and/or wire mesh may be formed of platinum (Pt) and/or Nickel(Ni).

Cathode 510 includes an electrically conductive wafer on which athermally stable soft magnetic material is to be deposited. As can beseen in FIG. 5 , the wafer 510 has an exposed surface 511 on which thethermally stable soft magnetic material is to be deposited. Surface 511may include a photoresist pattern if only portions of surface 511 are tobe deposited with the thermally stable soft magnetic material. If nophotoresist pattern is included on surface 511, the thermally stablesoft magnetic material will be deposited on the entire exposed surface511. In some embodiments, the wafer may include an electricallyconductive substrate and an electrically conductive seed layer (e.g., aNiFe seed layer) with surface 511 being an exposed surface of theelectrically conductive seed layer. The cathode 510 may be releasablycoupled to, and supported by, an arm 513 which, with the help of controlcircuitry 502, immerses the cathode 510 into the container 506 fordeposition of the thermally stable soft magnetic material. In someembodiments, manual adjustments to a position of the arm 513 may becarried out in order to immerse the cathode 510 into the solution 514.Once the deposition process is complete, the wafer 510 with thethermally stable soft magnetic material layer deposited thereon may beremoved from the solution 514 by the arm 513 under the control ofcontrol circuit 502 and/or by manual adjustments of the position of thearm 513. The removed wafer 510 may then be detached from the arm 513. Inshould be noted that positioning the cathode 510 above the anode 508within container 506 provides certain advantages. For example, if athermally stable soft magnetic material layer is to be deposited on anumber of wafers, positioning the cathode 510 in a manner shown in FIG.5 allows for relatively rapidly attaching a first wafer to the arm 513,immersing the first wafer into the electrolyte substantially immediatelyafter its attachment to the arm 513, carrying out the deposition of thethermally stable soft magnetic material layer, removing and detachingthe first wafer, and then processing the next wafer in a similar manner.Further, bubbles that may be formed on the cathode 510 duringelectrodeposition move in an upward direction and may escape from theelectrolyte 514 instead of attaching to the cathode. In spite ofdifferent advantages with the cathode 510 positioned above the anode508, in certain embodiments, the positions of the cathode 510 and theanode 508 may be reversed.

In general, solution/bath/electrolyte 514 within container 506 mayinclude several compounds that are suitable for deposition of thethermally stable soft magnetic material layer. Examples of compoundsthat may be used to deposit a NiFeX thermally stable soft magneticmaterial on the wafer 510 are included in Table 1 below.

TABLE 1 COMPOUND RANGE/VALUE H₃BO₃ about 0.15 to about 0.6 moles/literNi²⁺ about 0.36 to about 0.78 moles/liter Organic additives <1gram/liter sodium lauryl sulfate or about 0.1 grams/liter sodium dodecylsulfate Fe²⁺ about 5 to about 20 millimolar X elements (e.g., Re, Ir,Os, etc.) about 0.1 to about 0.2 millimolar Fe³⁺ less than about 0.01moles/liter pH about 2 to about 3

Sources of Ni²⁺ and Fe²⁺ may include chlorides, sulfates andperchlorates, and X elements may be any salt including that element andthat is dissolvable in an aqueous solution. Solution or bath 514 maysubstantially constantly be stirred by reciprocating mixing element orpaddle 512, which travels back and forth (as shown by bidirectionalarrow 515) below surface 511 of the wafer 510. Paddle 512 is typicallyin close proximity with surface 511 and provides the agitation of thebath 514 with minimum turbulence. It should be noted that, instead of asingle mixing element or paddle 512, multiple paddles may be employed,with each of the multiple paddles having a stroke that is a fraction ofthe stroke of the single paddles.

In the embodiment if FIG. 5 , controller 502 includes pulse currentsupply circuitry 520, which is electrically coupled to anode 508, tocathode/wafer 510 and to cathodic thief element elements 516. Cathodicthief elements 516 may be in a substantially same plane as the anode 508and are included to steal current away from edges of the wafer 510, andthereby help ensure that the deposition on the wafer 510 is uniform. Itshould be noted that, in some embodiments, pulse current supplycircuitry 520 may be separate from controller 502. During operation, tosupply a pulse current, circuitry 520 may toggle the current betweenhigh and low values (e.g., circuitry 520 may be turned on and off forpredetermined intervals of time) to provide suitable depositionconditions. Table 2 below includes examples of deposition conditions.

TABLE 2 CONDITION RANGE/VALUE time that current supply about 40 to about400 milliseconds circuitry is on (t_on) time that current supply about500 to about 1000 milliseconds circuitry is off (t_off) pulse peakcurrent about 35 milliamperes/square centimeter to density (I) about 100milliamperes/square centimeter rate of formation of the about 40nanometers/minute to about 400 thermally stable soft nanometers/minutemagnetic material layer

An electrolyte provided as show in Table 1 and the conditions shown inTable 2 may be used in the apparatus of FIG. 5 to form(Niro₇₀₋₈₅Fe₁₅₋₃₀)₉₅₋₉₉X₁₋₅ with the following properties:

-   -   Stress between about 150 to about 250 mega pascals (MPa).    -   Saturation magnetization (Bs) between about 0.5 to about 1.5        Tesla.    -   Easy axis coercivity (Hce) between about 1 to about 4 Oersted.    -   Hard axis coercivity (Hch) between about 0 to about 0.4 Oersted.    -   Magnetic anisotropy field (Hk) between about 2 to about 7        Oersted    -   Magnetostriction about 2-3 X 10⁻⁶.

A reader bottom shield such a 222 of FIG. 2 may be formed using theelectrodeposition technique described above in connection with FIG. 5with the compounds and conditions shown in Table 1 and Table 2,respectively. As indicated earlier, embodiments of the disclosure mayalso be utilized to provide thermally stable soft magnetic ornonmagnetic materials for MEMS, micro-actuators, MRAM and inductorapplications. It should be noted that compounds in Table 1 may bedifferent for different embodiments. One example in which thermallystable nonmagnetic materials are useful is HAMR.

Referring back to FIG. 2 , in some embodiments, recording head 200 maybe a HAMR head that includes elements 280 for heating magnetic storagemedium 250 proximate to where write pole 205 applies the magnetic writefield to the storage medium 250. Elements 280 are shown as a single boxin FIG. 2 in the interest of simplification. At least one of elements280 (e.g., a non-magnetic element including Au and Cu) may be formed byan electrodeposition technique of the type described above in connectionwith FIG. 5 . Experimental results from magnetic layer embodiments aredescribed below.

FIGS. 6A, 6B and 6C show magnetic hysteresis loops obtained forNi_(78.5)Fe_(21.5). In FIGS. 6A, 6B and 6C, horizontal axis 602represents an applied magnetic field (H) in Oersted (Oe) and a verticalaxis 604 represents normalized flux. Further, in FIGS. 6A, 6B and 6C,loops 606A, 606B and 606C, respectively, are easy axis magnetic loopsand loops 608A, 608B and 608C are respective hard axis loops. Loops 606Aand 608A are easy axis and hard axis loops, respectively, for anas-deposited layer of Ni_(78.5)Fe_(21.5) (e.g., a Ni_(78.5)Fe_(21.5)layer that has not undergone annealing after deposition). Loops 606B and608B are easy axis and hard axis loops, respectively, for theNi_(78.5)Fe_(21.5) layer after it has undergone an easy axis anneal atabout 350-400° C. for about 2 hours. Loops 606C and 608C are easy axisand hard axis loops, respectively, for the Ni_(78.5)Fe21.5 layer afterit has further undergone a hard axis anneal at about 325-350° C. forabout 2 hours.

FIGS. 7A, 7B and 7C show magnetic hysteresis loops obtained for NiFeX(where X=Re, Os, Ir, Pt, Rh, Pd, Ag, etc.). As in the case of FIGS. 6A,6B and 6C, in FIGS. 7A, 7B and 7C, horizontal axis 602 represents anapplied magnetic field (H) in Oersted (Oe) and a vertical axis 604represents normalized flux. Further, in FIGS. 7A, 7B and 7C, loops 706A,706B and 706C, respectively, are easy axis magnetic loops and loops708A, 708B and 708C are respective hard axis loops. Loops 706A and 708Aare easy axis and hard axis loops, respectively, for an as-depositedlayer of NiFeX (e.g., a NiFeX layer that has not undergone annealingafter deposition). Loops 706B and 708B are easy axis and hard axisloops, respectively, for the NiFeX layer after it has undergone an easyaxis anneal at about 350-400° C. for about 2 hours. Loops 706C and 708Care easy axis and hard axis loops, respectively, for the NiFeX layerafter it has further undergone a hard axis anneal at about 325-350° C.for about 2 hours.

From FIGS. 6B and 6C, it is seen that magnetic properties ofNi_(78.5)Fe_(21.5) deteriorate after high temperature annealingoperations. In contrast, from FIGS. 7B and 7C, it is seen that themagnetic properties of NiFeX remain excellent after the high temperatureannealing operations, thereby showing that NiFeX is substantially morethermally stable than Ni_(78.5)Fe_(21.5).

FIGS. 8A, 8B and 8C relate to Ni_(78.5)Fe_(21.5), FIGS. 9A, 9B and 9Crelate to NiFeX₁ (1 atomic percent (at %) Re) and FIGS. 10A, 10B and 10Crelate to NiFeX₂ (2 at % Re). FIGS. 8A, 9A and 10A are images, generatedfrom transmission electron microscopy (TEM), of layers ofNi_(78.5)Fe_(21.5), NiFeX₁, and NiFeX₂, respectively, which show animprovement in grain stabilization in NiFeX₁ over Ni_(78.5)Fe_(21.5),and a further improvement in grain stabilization in NiFeX₂. FIGS. 8B, 9Band 10B are images, generated from a magnetic force microscope (MFM), oflayers of Ni_(78.5)Fe_(21.5), NiFeX₁, and NiFeX₂, respectively, whichshow a reduction in magnetic out of plane noise in NiFeX₁ overNi_(78.5)Fe_(21.5), and a further reduction in magnetic out of planenoise in NiFeX₂. Additionally, an improvement in magnetic softness isseen in NiFeX₁ over Ni_(78.5)Fe_(21.5), and a further improvement inmagnetic softness is seen in NiFeX₂.

FIGS. 8C, 9C and 10C show magnetic hysteresis loops obtained forNi_(78.5)Fe_(21.5), NiFeX₁, and NiFeX₂, respectively. In FIGS. 8C, 9Cand 10C, horizontal axis 602 represents an applied magnetic field (H) inOe and vertical axis 604 represents flux in nanowebers (nWb). Further,in FIGS. 8C, 9C and 10C, loops 800, 900 and 1000, respectively, are easyaxis magnetic loops and loops 802, 902 and 1002 are respective hard axisloops. From FIGS. 8C, 9C and 10C, an improvement in magnetic softness isseen in NiFeX₁ over Ni_(78.5)Fe_(21.5), and a further improvement inmagnetic softness is seen in NiFeX₂. This demonstrates that doping NiFewith X (e.g., Re) has a positive influence on thermal stability,microstructure and magnetic properties.

FIG. 11 is a graph 1100 that shows a presence of a composition gradientin a patterned wafer. In FIG. 11 , horizontal axis 1102 represents adistance away from a surface of the patterned wafer in micrometers (um)and vertical axis 1104 represents nominal Re %. Points 1106 are for afeature having a radius of 5 um, points 1108 are for a feature having aradius of 10 um, and points 1110 are for a feature having a radius of 15um. From FIG. 11 , it is seen that a composition gradient exists in thepatterned feature, and Re at % increases with film growth in thefeature. It is further seen from FIG. 11 that the smaller the feature,the more significant the composition gradient.

FIG. 12 is an image of a NiFeX layer formed using galvanostatic plating(e.g., 100 mA/cm²) and subjected to high temperature annealing. As canbe seen in FIG. 12 , there are substantially large grains at a bottom ofthe layer due to the composition gradient described above in connectionwith FIG. 11 .

FIG. 13A is an image of an NiFeX layer formed using stepped currentplating (e.g., I₁-I₂-I₃-I₄-I₅ mA/cm²) and subjected to high temperatureannealing. The image of FIG. 13A shows a substantially uniform grainstructure due to composition homogeneity. An example of a steppedcurrent waveform utilized to form the NiFeX layer is shown in FIG. 13B.As can be seen in FIG. 13B, the waveform is a pulsed current with thet_on peak current changed (e.g., increased) in steps (I₁-I₂-I₃-I₄-I₅)after predetermined time intervals. Accordingly, the current appliedduring electrodeposition may be a combined stepped and pulsed currenthaving a form shown in FIG. 13B. It should be noted that, in theinterest of simplification, the peak current is shown as changing after4 pulses. However, in different embodiment, the peak current may bechanged after any suitable number of pulses. Also, different steps shownin FIG. 13B may have same or different numbers of pulses in differentembodiments.

FIG. 14A shows a Kerr domain image of a Ni_(78.5)Fe_(21.5) layer aftercarrying out an annealing operation on the Ni_(78.5)Fe_(21.5) layer.FIG. 14B shows atomic force microscope (AFM) and MFM images of a portion1400 of the Ni_(78.5)Fe_(21.5) layer shown in FIG. 14A. FIG. 15A shows aKerr domain image of a NiFeX₂ layer after carrying out an annealingoperation on the NiFeX₂ layer. FIG. 15B shows AFM and MFM images of aportion 1500 of the NiFeX₂ layer shown in FIG. 15A. A comparison of FIG.14B and 15B shows that, after a high temperature anneal is performed onNi_(78.5)Fe_(21.5) and NiFeX₂, domain stability of NiFeX₂ is greatlyimproved compared with Ni_(78.5)Fe_(21.5). In general, after a hightemperature anneal, domain stability of NiFeX is greatly improvedcompared with Ni_(78.5)Fe_(21.5).

The illustrations of the embodiments described herein are intended toprovide a general understanding of the structure of the variousembodiments. The illustrations are not intended to serve as a completedescription of all of the elements and features of apparatus and systemsthat utilize the structures or methods described herein. Many otherembodiments may be apparent to those of skill in the art upon reviewingthe disclosure. Other embodiments may be utilized and derived from thedisclosure, such that structural and logical substitutions and changesmay be made without departing from the scope of the disclosure.Additionally, the illustrations are merely representational and may notbe drawn to scale. Certain proportions within the illustrations may beexaggerated, while other proportions may be reduced. Accordingly, thedisclosure and the figures are to be regarded as illustrative ratherthan restrictive.

One or more embodiments of the disclosure may be referred to herein,individually and/or collectively, by the term “invention” merely forconvenience and without intending to limit the scope of this applicationto any particular invention or inventive concept. Moreover, althoughspecific embodiments have been illustrated and described herein, itshould be appreciated that any subsequent arrangement designed toachieve the same or similar purpose may be substituted for the specificembodiments shown. This disclosure is intended to cover any and allsubsequent adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b) and is submitted with the understanding that it will not be usedto interpret or limit the scope or meaning of the claims. In addition,in the foregoing Detailed Description, various features may be groupedtogether or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments employ morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all of the features of any of the disclosed embodiments.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true spirit and scope of the present disclosure. Thus, to themaximum extent allowed by law, the scope of the present disclosure is tobe determined by the broadest permissible interpretation of thefollowing claims and their equivalents, and shall not be restricted orlimited by the foregoing detailed description.

What is claimed is:
 1. A recording head comprising: at least one of aread head or a write head; and at least one thermally stable featureformed of a material having grains that include at least one element anda first dopant: with each of the grains of the material having a sizebetween about 6 nanometers and about 12 nanometers; wherein the at leastone thermally stable feature comprises a first thermally stable featurethat includes at least one read head shield; wherein the first dopant ofthe at least one read head shield comprises a 4 d or 5 d transitionelement comprising Re, Os, Ir, Pt, Rh, Pd or Ag; and wherein an atom ofthe first dopant is within the grain of the material.
 2. The recordinghead of claim 1 and wherein the at least one element of the at least oneread head shield comprises at least one magnetic element including afirst magnetic alloy element and a second magnetic alloy element.
 3. Therecording head of claim 2 and wherein: the first magnetic alloy elementcomprises Ni; and the second magnetic alloy element comprises Fe.
 4. Therecording head of claim 2 and wherein the at least one thermally stablefeature further comprises a second thermally stable feature thatincludes a heating assistance feature, and wherein the at least oneelement of the heating assistance feature comprises Au, and wherein asecond dopant of the heating assistance feature comprises Cu.
 5. Therecording head of claim 1 and wherein the atom of the first dopant has asize that is substantially different from a size of an atom of the atleast one element.
 6. The recording head of claim 1 and wherein the atomof the first dopant is surrounded by a plurality of atoms of the atleast one element within the grain.
 7. The recording head of claim 1 andwherein the read head comprises a tunnel magnetoresistance head.